1. Field of the Invention
This invention pertains to food processing machines, and more particularly to food processing machines capable of high production of individual food products for each cycle of a mold plate.
2. Description of the Prior Art
Various types of machines have been developed to form individual items of food products from a bulk supply of food material. For example, U.S. Reissue Pat. No. 30,096 describes a prior machine capable of producing individual patties from a bulk supply of ground meat. U.S. Pat. No. 4,872,241 shows a machine for making individual nuggets from whole muscle meat.
FIGS. 1 and 2 show in schematic form a typical prior machine 4 that processed bulk food material 6 into individual items 40. The particular machine 4 was a Model F19 machine manufactured by Formax Company of Mokena, Ill. The Formax machine was highly successful in processing large quantities of bulk food material 6 into typical food items 40 such as poultry nuggets and beef patties.
The food material 6 was stored in a hopper 26. The hopper 26 opened into a pump box 48 that had a top plate 22. The top plate 22 had a back edge 24 and a front edge 70. Inside the pump box 48 was a plunger 44. The hopper, pump box, top plate, and plunger 44 were major and permanent components of the prior machine 4. Changing any of those components was a major undertaking. Consequently, for practical purposes, the top plate back and front edges 24 and 70, respectively, were permanently fixed on the machine.
The prior machine 4 further comprised a drive linkage 8 that included a slide plate 10. The drive linkage 8 reciprocated the slide plate 10 in longitudinal directions 14 and 16. The drive linkage 8 depicted in FIGS. 1 and 2 represents a cam and follower mechanism that was standard equipment for the prior Formax machine. The cam and follower mechanism reciprocated the slide plate with a nine inch stroke. Like the machine pump box 48 and top plate 22, it was difficult to change the stroke of the drive linkage. International Patent Publication Number WO 02/102166 A1 confirms the difficulty of changing the stroke length of the prior food processing machine.
Hinged to the slide plate 10 was a mold plate 12. Accordingly, the mold plate 12 also reciprocated with a nine inch stroke. In the mold plate 12 were a number of cavities 38. The cavities 38 could be of different shapes, such as round, elliptical, or irregular. The cavities were arranged in one or more rows transverse to the longitudinal directions 14 and 16.
The mold plate 12 was located between a fill plate 20 and a breather plate 18. The fill plate 20 was adjacent the pump box top plate 22. The fill plate had one or more fill slots 36 through it. The fill plate 20 had a back edge 72 and a front edge 75 that were spaced approximately 12 inches apart. The breather plate 18 was spaced from the fill plate by a distance slightly greater that the thickness of the mold plate. The breather plate had back and front edges 77 and 79, respectively, that were generally aligned with the fill plate back and front edges 72 and 75.
The drive linkage 8 reciprocated the slide plate 10 and mold plate 12 between a fill position and an eject position. When the mold plate was in the fill position, FIG. 1, the cavities 38 were located so as to be in communication with the fill slot 36 in the fill plate 20. At that point, the plunger 44 operated to pump food material 6 from the pump box 48 through an opening 76 in the top plate 22, through the fill plate fill slot, and into the mold plate cavities. Air in the cavities was forced into small holes in the breather plate 18 and vented to the atmosphere. When the cavities were filled, the drive linkage reciprocated the mold plate to the eject position, FIG. 2. At the eject position, the mold plate cavities were beyond the front edge 79 of the breather plate and the front edge 75 of the fill plate. A knockout mechanism 71 reciprocated in vertical directions 73 to eject the food product from the cavities in the form of individual items 40.
In the prior machine 4, there was a limited area of the mold plate 12 that could be used for the cavities 38. That area, called the fill area, was determined by the maximum usable transverse width of the mold plate and by the longitudinal fill length. The fill length was the maximum longitudinal length of the mold plate that could be used for the cavities 38 and is shown as dimension X. The fill length X was limited by several factors, including the distance from the leading edges of the cavities closest to the fill plate front edge 75 when the mold plate was at the fill position, by the distance from the trailing edges of the cavities closest to the fill plate back edge 72 when the mold plate was at the fill position, and by the length of the stroke of the mold plate. In the prior machine, the fill length was approximately six inches, or 67 percent of the stroke length of nine inches. Consequently, one row of six inch diameter cavities was the maximum cavity size that could be incorporated into a prior mold plate. Another cavity pattern, as shown, was two rows of relatively small cavities having approximately two inch diameters.
Unlike the pump box 48, top plate 22, hopper 26, and plunger 44, the mold plate 12, fill plate 20, and breather plate 18 were rather easily installable into and removable from the machine 4. In fact, a particular set of mold plate, fill plate, and breather plate was considered as a tooling set that was interchangeable within the machine with another tooling set of mold plate, fill plate, and breather plate to suit different items 40 and food material 6. It was common practice to provide a machine with several tooling sets that were interchangeably installed and removed from the machine to suit the production requirements at hand.
The production of the prior machine 4 as measured by pounds of material per unit time was limited by the fill area of the mold plate 12 and by the operating speed. If the fill area was utilized to the maximum, the only way to increase the production of the prior machine was to increase its speed of operation. However, the operating speed was limited by vibrations and excessive wear.
U.S. Pat. No. 4,996,743 demonstrates a drive linkage for a mold plate of a food processing machine. The drive linkage of that patent included a hydraulic system that imparted a dwell time to the mold plate when the mold plate was at its fill and eject positions. The drive linkage enabled an input member to rotate continuously but allow proper filling and ejection of cavities in the mold plate. Although the drive linkage of the U.S. Pat. No. 4,996,743 patent worked quite well, it did have certain limitations. Most important, the drive linkage was limited to a mold plate stroke of about nine inches.
Thus, a need exists to upgrade the production capabilities of food processing machines.
In accordance with the present invention, a food processing machine is provided that increases production without increasing machine operating speed. This is accomplished by converting a prior top fill food processing machine to increase its mold plate stroke and mold plate fill area.
The food processing machine of the invention may be conventional in several respects. A prior machine suitable for converting is a Formax F19 machine. The prior machine comprises a frame, a hopper that holds a quantity of bulk food material, a pump box, and a top plate that is part of the pump box. The hopper, pump box, and top plate are utilized without change in the present invention. Accordingly, the dimensional relationships between the foregoing components do not change.
Increasing the mold plate fill length is achieved through the cooperation of two major structural components that are changed from the prior machine: tooling and a drive mechanism. The tooling of the invention includes the mold plate, a fill plate, and a breather plate. Different tooling sets of mold plates, fill plates, and breather plates can be rather easily installed into and removed from the machine. The different tooling sets of tooling are interchangeable in the machine to suit the particular food processing requirements at hand.
The fill plate is installed under the pump box top plate. The fill plate has one or more fill slots that communicate with the pump box through an opening in the top plate. The mold plate is under the fill plate, and the breather plate is under the mold plate. The mold plate has a series of cavities in it that are sized and shaped to suit the particular food product to be produced from the bulk material. The mold plate reciprocates in longitudinal directions between a fill position and an eject position in response to operation of the drive mechanism.
When the mold plate is at the fill position, food material is pumped from the pump box through the opening in the top plate. The material flows in a downward direction and enters the fill slots in the fill plate, and then flows into the cavities in the mold plate. After the cavities have been filled, the mold plate slides in a forward stroke. Depending on the configuration of the cavities in the mold plate, some cavities may come into communication with the fill plate fill slots only while the mold plate is moving. Ultimately the mold plate reaches the eject position, where individual items are ejected from the cavities.
To increase the mold plate fill area, the mold plate, fill plate, and breather plate are designed with increased longitudinal lengths compared to prior tooling. The relative locations of the fill plate fill slots and the mold plate cavities are also changed in mutually dependent ways. A critical dimension of the invention is the seal-off length. The seal-off length is the distance between the leading edges of the cavities closest to the mold plate leading edge and the front edge of the fill plate when the mold plate is at the position where those cavities lose communication with the fill slots as the mold plate slides in a forward stroke. The seal-off length assures that food material does not flow out the cavities closest to the mold plate leading edge when those cavities are still in communication with the fill slots. To achieve adequate seal-off, the front edge of the fill and breather plates extend forwardly beyond their respective locations in the prior machine. In addition, the interplay between the increased mold plate stroke, the breathing requirements of the cavities, and the seal-off length requires that the back edges of the fill and breather plates extend rearwardly from their respective locations in the prior machine.
Any increase in mold plate fill length above the prior six inch fill length will increase the production of the prior food processing machine without increasing operating speed. We have found that a fill length of approximately 8.50 inches can be obtained by means of the present invention with little or no changes to the major and permanent components of the prior food processing machine such as the pump box and top plate. A fill length of 8.50 inches represents an increase of 42 percent over the fill length of the prior machine.
As mentioned, the dimensional relationships between the hopper, pump box, and top plate do not change when different tooling is installed in the machine. Consequently, the foregoing components are used as references for converting the prior machine in accordance with the present invention. Specifically, it is highly desireable to use the back edge of the top plate as a fixed reference for the tooling. That procedure contributes to the efficient ability of converting the prior food processing machine to accept the interchangeable tooling sets according to the present invention.
To reciprocate the mold plate, the food processing machine further comprises the drive mechanism. In the preferred embodiment, the drive mechanism includes a motor and a speed reducer that rotate a crank arm at a constant speed. The crank arm acts through a lost motion cylinder to oscillate a lever. One arm of the lever is connected to a slide plate. In turn, the slide plate is hinged to the mold plate. A block on the slide plate contacts a stop on the machine frame when the mold plate is at the eject position. In that manner the location of the mold plate at the eject position is accurately controlled, which is important for proper ejection of the items from the mold plate cavities.
The drive mechanism is designed to impart a 12 inch stroke to the slide plate and mold plate. That stroke is three inches or 33 percent greater than was possible with the prior machine and contributes to the increase in the mold plate fill length to approximately 8.50 inches. It is thus seen that the present invention provides a fill length that is approximately 71 percent of mold plate stroke length.
The method and apparatus of the invention, using changed tooling and drive mechanism, thus increase the capacity of a prior food processing machine without increasing the operating speed. Different tooling sets are interchangeably installable into and removeable from the machine to suit different product requirements, even though the same increased mold plate stroke is always used.
Other advantages, benefits, and features of the invention will become apparent to persons skilled in the art upon reading the detailed description of the invention and studying the drawings.